Masteries

Offense:
1

Defense:
21

Utility:
8

So you wanna play Malphite hm? Malphite is one of my favorites and top 5 most used champs. I've tried all kinds of builds - Brutal Strikes DPS, Hybrid Shard/Strikes Burst/DPS, Pure AP Burst, and all seemed to fail me.
However, I found that building him tanky and boosting that E skill gave him the survivability he needs while also giving him nice AoE damage. Note that his E skill - Ground Slam - gains more damage the more you stack armor.. hmm.. interesting.

WARNING: Wall of Text Below

-(Masteries and Spells}-
I like going full 21 down the defense tree since we are indeed playing tank. You can either hit the Archaic Knowledge in Offense Tree for more Magic pen or (if you like being more conservative) grab some extra regeneration and Mana in the Utility Tree. I run Exhaust/Ghost and find the single offense mastery Cripple to help more than 1 gold/10s. Nimbleness+Ghost will get you out of sticky situations, and Exhaust+Ghost+Shard will get you the kill on that runner.

-{Runes}-
Magic Pen for marks. You may be the tank or off-tank but your main damage with this build in fights is magic damage, you need that pen.
Dodge OR Scaling Armor for your seals. Dodge helps with the Nimbleness mastery and Armor adds a little to survivability and your E burst.
Cooldown Reduction (Flat or Scaling) for Glyphs. The scaling runes only surpass the flat runes when you hit 14, but they are still a good choice.
For quintessences, I like the flat hp, giving you good early game survivability. Adding to any of the stats of the above mentioned normal runes is also a good choice, and you can also consider movement speed for that nice escape/chase boost to add to your already amazing chase combo.

-{Items}-
You start out with Sapphire Crystal and 2 Health pots. Gives you enough mana to harass properly with Shard in the start and you have some health regen if they harass back.
First trip back, if you haven't died yet, pick up the catalyst. If you got a couple kills early, you should be able to grab this before level 6, giving you great harassment power with the recovery after levelling. Grab boots of speed right after this.
Take the boots suited to the enemy that seems to be the best or most fed. That enemy Yi has 3 kills already in the other lane? Grab Ninja Tabi, Mercury's for mages. Sorcerer's are also viable if you're doing good.
Now we can get what we really are here for - armor. Sunfire cape is a great great item for you, Malphite user. Health, Armor, Light AoE damage. When you execute your ability combo, (more on it later) the sunfire cape adds some nice extra damage with its passive.
Guardian Angel and Banshee's Veil (upgraded from Catalyst) are the last parts of your core item build. They will let you initiate while shrugging off the initial bursts the enemy throws at you. If they are silly enough to keep focus on you, GA saves the day. That should be long enough for your team to eat the enemy alive.

The rest of the items, if the game isn't over, are armor counters.
Thornmail+health regen armor(Force of Nature/Warmog's) for hard dps carrys (Yi, Tryndamere, Tristana, DPS Ashe, DPS Teemo, etc).
Another combo to fight attackers is Randuin's Omen and Frozen Heart. They give you 40% Cooldown reduction allowing you to burst, chase burst more.
*note* The Brutalizer in the items list is a component of Randuin's Omen. Omen has not been added to the site yet.
If you are unsure of what to do, you can just stack on 2 more Sunfire capes, get in their face, more health = more sitting in front of them with Sunfire damage, more armor = more burst E damage.

-{Skills}-
Yes we are building a tank, but as you can see with items build, (unless you are guaranteed to grab Ninja Tabi) you aren't getting much armor until the 3rd item. Grab Shard, Strikes and Shard again. We grab Strikes at level 2 to help with creep farming and at level 3, you have your harass and chase tool for the next while. Harass them enough, and you will get your armor before they get in gear. I see many Malphite builds maxing Shard first... WRONG. Not for tank Malphite my friend. Shard gains damage, but 10 more mana cost per level. It'll be a sad day when your enemy runs away from you when you are 15 mana below throwing that last Shard.
Starting level 4, max out your Slam and grab your ult on the way. Your combo is pretty much here. Grab your Ult at 11 and 16 and continue with maxing Shard then Strikes last. You are still listed as a carry, and if the game still goes on this long, Strikes will help your tower pushing power. Simple as that.

-{Playing}-
As Armor Malphite you SHOULD be taking a side lane. Ashe and Teemo and the like will eat you solo mid.

Level 1 lane gank - if you get to the bush first, sit and wait for them to come in the bush. Whoever your partner focuses on, hit them with a normal attack or two and shard as they run. Easy.
Early game - You want to focus on last hitting minions. Run in front with your melee creeps and punch punch punch slap punch for gold. If the enemy feels like going for some damage on you,run to your caster creeps, then shard them. They will back off if they do not want to die to your caster creeps. If you are babysitting a hard carry or a melee dps, stay in front and just move around the sides of the creep line. You're there to scare them away with a Shard if they come too close to your baby.
After getting catalyst, you have great lane staying power. Be a little more conservative with your shards if you are at half mana. Now we'll learn the skill combo.

--> THE COMBO <--
Your side initiating -> Press R and ult slightly behind them, and activate Brutal Strikes as you reach them. Use Ground Slam and start slapping the weakest enemy with melee hits. Shard as they attempt escape.
Enemy side initiating -> Press R and target your ult right on top of your ally being focused, or where they will be in the next second if they are being chased. Pop Strikes, Slam, melee, Shard. Done. Back to the 'playing' section.

Early Skirmishes - Now that we know your combo, feel free to pop into another lane and combo into a 2v2/3v2 fight. Around level 7-9, your burst will scare away most enemies or save your team long enough for a tower dash and blue pill. If there is a straggler left, ghost up and slow them with Shard. Your team can then crush that little sucker for not running to fountain when he had the chance.

Mid/late game fights. At this point, it's probably going to full on 5v5s or 5v4s if some carry feels like pushing a lane while the other side is distracted. Although the combo has amazing damage, you should be second into the fight, not first. As the enemy start tossing skills at your main tanker, combo in and let your dps/carry own lolwut200hpleft face. If there is a carry kicking around by being outside of combo range or something, throw exhaust on him quickly after using the combo to keep your team alive. Leftover should be Ghost chased, Sharded, and bursted down.

Alternate to the Combo (For high health initiations) -> Save your ult and simply open with a Shard and then Slam them when in range. This is for small 2v2/2v3/3v3 skirmishes when both sides still have 80%+ health. Shard -> Slam -> Strikes. As the fight gets to 40/50% health, ult into your combo. Rage will ensue.

-{Closing}- So anyways, that's just the way I like Malphite since it works best for me. You and your tank will easily take non-focused damage with all the armor you stack, and your GAngel+BVeil will help against the mages. With all that armor, you should be sitting there long enough for a combo, a second damage burst with Slam and Shard, all while your Sunfire cape burns the foolish who stay against your team. This is how I play Malphite, so give it a try, leave a comment after the try, and hope you enjoy.